Process for the manufacture of titanic oxide



m s Nov. 15, .1927.

UNITED STATES PATENT OFFICE.

nomn'r srncn'r, or :enaLiN-onmmnnuns, (1mm.

:enocnssrog TEE mun-scrum: or m met c oxmn.

Io Drawing. Application fled Kay 18, 1925, Serial No. 81,324, and in Germany I lllay 24, 1824.

' simultaneously it mus possess the property of a well covering paint. A processds known for obtaining a well covering paint of titanic dioxide, which is characterized in that the strongly acid solutions of sulphate of titanium are subjected to hy'drolytic decomposition under pressure.

Exhaustive investigation has proved that with this rocess under predetermined working con itions an optimum is obtained as regards the absence of iron and the covering property. In addition it was found,

that under these workin conditions theoptimum of the absence 0 iron and the optimum of the covering property will almost coincide. The decisive conditions for a success are the following: the contents of free acid in the solution, the absolute concentration of said solution and the temperature for hydrolysis.

best results were It has been found that the obtained when hydrolysis is effected at temperatures ranging from 170 t0'180 degrees centigrade, but at any rate .not falling below 160 degrees centigrade, namel with the aid of a solution of sulphate of t1tanium, whose specific avity is about 1.5 and whose sulphuric acid content is about sulphuric acid and that'bOund to the titanium being taken as a whole.

According to the temperatures maintained within the limits'indicated the s ecific gravity and the contents of acid might be chosen the higher the, lower the temperature of the solution tobe h drolyzed is kept. The admissible limits or the specific gravity and the acid contents for the range=of tempera-- tures mentioned, thatisto say from 160 to ter between 40 and 25 or at the most per.

. 180 degrees centigrade, fluctuate for the former between 1.55 and 1.35 andfor the latcent .of total acid contents.

The specific gravity being decisive for the per cent by weight, the free P successful result, can also be obtained by I adding neutral soluble salts as for instance a sulphate, particularly the sulphate of an alkali metal, that is to say, of a metal whose oxide is white. If no importance is attached to the product being free from iron,

a well covering titanic acid can be obtained in the event of the specific gravitybeing too low,by adding iron. sulphate to such an extent, that the solution will have a specifi gravity from about 1.4 to 1.5. I

I claim: I

1. In the manufacture of white well covering titanic oxide free from iron, the process of hydrolyzing at temperatures from 160 to 180 degrees centigrade by means of solu tions having a specific gravity ranging from 1.35 to;:1.55 and the total acid contents of said solutions ranging from 25 to 40 per cent.

2. In the manufacture'of pure white well covering titanic oxide free from iron, the process of hydrolyzing at temperatures from 160 to 180 degrees centi ade by means of solutions having a speci c gravity ranging from 1.35 to 1.55, the total acid contents of said solutions ranging from 25 to 40 per cent, and obtaining the desired specific avity of from 1.35 to 1.55 bythe additionof soluble sulfates of metals whose oxides are white.

3. In the manufacture of pure white well covering titanic oxide free from iron, the rocess of hydrolyzing at temperatures from 1 160 to 180 degrees centigrade by means of solutions having a specific gravity ran from 1.35 to 1.55 the total acid contents 0 said solutions ranging from 25 to 40 per cent, and obtaining the desired s ecific gravity of from 1.35 to 1.55 by ding alkali metal sul hates. v r

4. In the manufacture; of well covering titanic oxide, the process of hydrolyzing at temperatures from 160 to 180 degrees centi ade by means of solutions having a speci 0 gravlty. ran 'ng from 1.35 to 1.55.

4 In testimony w ereof I aflix my signature.

DR. NORBERT SPECHT. 

